Bacterial biofilms develop in a variety of bodily cavities, including those of the ear, such as the middle ear, and of the nose, such as the frontal or maxillary sinuses, for example. Once bacterial growth has been established, the bacteria will often aggregate, stop dividing, and begin forming protective bacterial biofilm layers, or “slime layers,” comprised of polysaccharide matrices.
The protective bacterial biofilm interferes with the body's natural immune response as well as traditional methods of treatment. In particular, the bacteria emit exotoxins, which incite the body's immune system to respond with white cells. However, the bacterial biofilm interferes with the efficacy of the white cells' ability to attack the bacteria. The biofilm can also act as a barrier against topical administration of antibiotics and other medicaments. Biofilm-forming bacteria also present obstacles to traditional, antibiotic treatments that act to kill dividing bacteria. In particular, the bacteria in a biofilm-forming state may have already ceased cell division, rendering such antibiotics largely ineffective.
For example, relative to chronic rhinosinusitis and other similar ailments, bacteria in the nose can be viewed as a continuum. Some bacteria (e.g., certain strains of pseudomonas and staph aureus) form robust biofilms. Others (e.g., h. flu) form relatively mild biofilms. The biofilms may or may not include or contain fungi. Each of these microbes has a somewhat different or complimentary inflammatory pathway and interacts with the host's immune system differently. For example, staph aureus produces a lipopolysaccharide matrix that acts as an antigen and causes a host response, as well as toxins (e.g., staph exotin A and B, toxic shock syndrome toxin 1 and 2) that can produce an antigenic and even hyperantigenic superantigenic (hyperinflammatory) response. Recent literature suggests that chronic rhinosinusitis is an inflammatory response to bacterial biofilms. Other microbes can also produce inflammatory-inciting toxins. The sessile nature of the underlying bacteria and the tenaciousness of the biofilm make them difficult to treat.
Functional endoscopic sinus surgery (FESS) is a minimally invasive surgical procedure used to treat chronic rhinosinusitis, and possibly other infections of the sinuses. FESS opens up sinus air cells and sinus ostia (openings) with an instrument aided by an endoscope. The use of FESS as a sinus surgical method has now become widely accepted. The purpose of FESS is typically to restore normal drainage of the sinuses and to allow their ventilation. However, FESS does not address the bacterial biofilm concerns described above.
While ventilation surgery may incidentally cause some biofilms to slough off, many remain after surgery and it has been postulated that further therapies are required to remove bacterial biofilms in the paranasal sinuses and other bodily locations.